security/strongswan: Update to 5.9.4

Security & Bugfix Update to 5.9.4:

• Changelog: https://github.com/strongswan/strongswan/releases/tag/5.9.4
• While here change repos to https
• Fix CVE-2021-41990: https://www.strongswan.org/blog/2021/10/18/strongswan-vulnerability-(cve-2021-41990).html
• Fix CVE-2021-41991: https://www.strongswan.org/blog/2021/10/18/strongswan-vulnerability-(cve-2021-41991).html

PR: 259267
Approved by: strongswan@Nanoteq.com (maintainer)
MFH: 2021Q4

(cherry picked from commit eead2ddf757a4e9f50eedd1680f3b62e6a16aaef)